Mycoplasma hyopneumoniae is the etiological agent of swine Mycoplasmal pneumonia (also called enzootic pneumonia (EP)). It is one of the most common and economically significant respiratory diseases affecting swine production worldwide. The disease is associated with secondary infections, high-morbidity and low-mortality rates, low feed conversion and can be attributed to global economic losses estimated at about $1 billion per year.
In EP, Mycoplasma hyopneumoniae bacteria attach to the cilia of epithelial cells in the lungs of swine destroying healthy normal cilia allowing for opportunistic organisms to establish themselves into the respiratory tissue causing disease. Once established, M. hyopneumoniae causes lesions in the lungs of pigs.
The disease is highly contagious and transmission is usually through direct contact with infected respiratory tract secretions, for example droplets ejected from the snout or mouth on sneezing or coughing.
Several vaccines against M. hyopneumoniae currently exist. Most current vaccines are provided by about 10 companies with 22 vaccine brands registered as either single or bi/multivalent. All are killed or inactivated M. hyopneumoniae preparations.
Examples of whole cell inactivated M. hyopneumoniae vaccines include RESPISURE™ and STELLAMUNE™ (Pfizer), SUVAXYN M. HYO™ (Fort Dodge), HYORESP™ (Merial), M+PAC™ (Schering-Plough) and PORCILIS™ (Intervet).
While some vaccines can reduce the severity of EP, none of the available whole cell killed or inactivated vaccines provide full protection from M. hyopneumoniae infection.
Our co-pending application, published as WO2010/132932, describes a live attenuated M. hyopneumoniae strain which is temperature sensitive. This strain is designated ts-19 and was deposited under the Budapest Treaty at the National Measurements Institute as NM 04/41259 on 13 May 2004. This strain, when incorporated into a vaccine, is able to confer protective immunity against M. hyopneumoniae in vaccinated pigs.